Presence of Antibiotic Resistant Staphylococcus aureus in Sewage Treatment Plant

Anthony Naquin, Jacob Clement, Mary Sauce, Richard Grabert, Mingma Sherpa, Raj Boopathy



Antibiotic resistance has become very common in the world. After passing through the human or animal body the antibiotics are entered into the sewage treatment plant, where water is processed and cleaned then returned into the environment. During the sewage treatment process, antibiotics come into contact with bacteria entering the treatment process, as well as bacteria used in the treatment process. The bacteria that are exposed to these antibiotics can become resistant during the treatment process and then expose the antibiotic resistance genes (ARGs) to the environment upon release of treated water from the treatment plant. Because of the contact between bacteria and antibiotics during the treatment process, sewage treatment plants are considered prime habitat to create antibiotic resistant bacteria. There are very limited studies on this subject from a small town sewage treatment plant. Therefore, this study was conducted using raw sewage as well as treated sewage from Thibodaux sewage treatment plant, which serves 15,000 people in rural southeast Louisiana of USA. Samples were collected monthly from Thibodaux sewage treatment plant and antibiotic resistance was monitored using Kirby-Bauer assay. Special attention was given to Methicillin Resistant Staphylococcus aureus (MRSA) in raw and treated sewage samples for the five month of the study period. Results showed the presence of MRSA consistently in both raw and treated sewage. The presence of mecA gene responsible for Methicillin resistance was confirmed in isolates of pure culture of S. aureus as well as in the sewage samples.


Keywords: Sewage treatment; antibiotic resistant; mecA gene, free DNA; Staphylococcus aureus; genetic transformation